1. Field of the Invention
The present invention pertains to an optical addressing device and its use in electro-optical imaging devices.
The invention applies especially to the making of imaging devices wherein optical addressing is used to reveal each pixel of a previously recorded latent image, in the form of either an electrical or a light signal.
The invention also applies to display devices for the presentation of information and to the making of display screens for image construction in medical imaging devices.
2. Description of the Prior Art
Optical addressing imaging devices of the prior art may be classified under two categories which are determined by the physical manner in which each pixel of a recorded image is revealed by the imaging device.
In the first category, descriptions of which can be found, for example, in the U.S. Pat. Nos. 4,446,365, 4,547,670 and DE No. 3,235,076, the effect of an optical reading excitation on each recorded pixel of the image produces an electrical signal.
In these imaging devices, the electrical charges photo-induced in recording are preserved for each pixel in a photoconductive device which has an inhibiting electrode. When reading, the charges trapped during the recording are compensated for by photo-induced charges, causing a current in the reading circuit which is proportionate to the number of charges compensated for, hence proportionate to the local intensity of the recorded image.
In the second category, for which a corresponding description can be found in the European Pat. No. 0,138,024, the latent image memorized during the recording is revealed directly in the form of optical signals through the action of the addressing devices.
Since, in these imaging devices, the image recording medium has a plane shape on which lies the matrix of the pixels of the recorded image, the addressing system applied is a Cartesian addressing system along the directions X and Y of the rows and columns of the matrix organization, and the reading of each pixel is done by the scanning of a thin pencil of light which illuminates each pixel located at the intersection of a row and a column of the matrix in a direction perpendicular to this plane. This addressing and reading mode, whether it is effected directly by a laser beam deflected in X and Y by means of mirrors or indirectly by means of an optic fiber set in a direction perpendicular to the matrix plane and shifted in X and Y facing each pixel of the matrix, is constrictive as regards both design (for the resulting product is bulky) and efficiency because of the electromechanical devices used which, by their nature, have limited speed of movement.
3. Summary of the Invention
The purpose of the invention is to remove the above disadvantages.
To this end, the object of the invention is an optical addressing device which can be used to move the luminous lines above determined zones of a surface and for the optical identification of these zones, a device comprising one or more lateral diffusion light guides arranged in a direction parallel to the surface, coupled by one end to a light source and to control means so as to selectively illuminate each zone of the surface by means of at least one light guide.
Other characteristics and advantages of the invention will appear below in the following description made with reference to the appended drawings of which: